Overheated Computers

[DRIFT-O-MATIC]

I returned home, from being gone on vacation for 8 days. When I walked into the house, I couldn't believe how hot it was. Before I left, I set my AC to 80 degrees; but it was a blistering 98, and over 100 in the room where my computers are! I live in Florida, and my ductwork is in the attic. The compressor quit working, but the circulating fan continued to run. All the ductwork is in the attic; so it just kept pumping hotter and hotter air throughout the house. The computer, that I kept running while I was away, was just racing like a jet engine. I immediately shut it down. It is a Dell Dimension 8300 desktop and is running W7. The other computer in the same room is a Dell Optiplex 280 desktop running WXP, which was turned off while on vacation. The Dimension is plugged into a UPS power backup. The Optiplex is plugged into the same UPS. However, it is plugged into the non-backup outlet. After shutting down the Dimension, I turned off the UPS to help cool down the room, because many other peripherals were plugged in to it.

After I got the AC fixed, I plugged in the UPS, and all of a sudden the Optiplex turned on, without pushing the power button. Well, I thought it was going to blow up, because the fan was running so fast and loud. It was way louder and faster than the Dimension, when I first arrived home. It wasn't booting up; it was just racing out of control. It was really scary; so I manually shut it down. I then fired up the Dimension…AOK. No problemo.

I've repeatedly tried turning on the Optiplex, with the same result. Has anyone experienced this phenomenon? What could have happened, and how can I fix it? Any advice would be appreciated.